Objectives: 1) To identify and characterize one or more important plasma membrane tumor-associated antigens (TAA's) in human lung cancer which are absent from late fetal and normal adult tissue and which are immunogenic in humans; 2) to determine the occurrence of the TAA('s) in host plasma and sputum, and to determine the status of host cellular and humoral immunity to the TAA('s); 3) to determine the relationships of the above parameters to the course of disease, to each other, and to therapy for the purpose of identifying parameters which can be measured to provide earlier and more accurate diagnosis, treatment, and assessment of prognosis.